Meridian Energy has spent more than $70 million trying to develop new hydro electricity schemes in the Waitaki Valley in South Canterbury and North Otago, but there is uncertainty over whether any of the ventures will power a single light bulb.

As Solid Energy's financial woes were revealed last week, a leading academic said the structure of state-owned enterprises (SOEs) rewarded using cash from assets they inherited to fund "speculative" ventures.

Figures released under the Official Information Act show Meridian, the largest state-owned company earmarked for partial privatisation by the Government, had spent $33.4m on the North Bank hydro project in South Canterbury by the time it put it on indefinite hold last month.

The company refused to give a breakdown of the cost, but it included "options agreements", under which farmers were paid large sums in return for an option to buy their land later. These will expire if the project does not go ahead within a certain time frame.

North Bank was conceived after Meridian pulled out of Project Aqua, an even larger hydro project on the opposite side of the Waitaki River. After Project Aqua was cancelled, ostensibly over water access issues, the company wrote off $38.7m against its costs.

The ventures leave Meridian, which boasts about its electricity coming from "100 per cent natural renewable resources" owning more than 3000 hectares of mainly dairy farmland, and managing three farms itself.

North Bank was put on ice in January because of flat demand, although Meridian admits it has other wind farm proposals in the pipeline that would take priority. Chief executive Mark Binns said the company would keep its resource consents live to keep open the option of building North Bank later.

"Would you start it all from scratch? Possibly you wouldn't, but we have this asset now and we have to evaluate it on that basis."

Since joining Meridian from Fletcher Building at the start of 2012, Binns has taken a knife to the company's project development pipeline, cancelling proposals for wind farms in Central Otago and West Coast hydro dams.

The company had already written off millions against its business ventures unit by the time Binns closed it last year. The unit spawned ventures such as heating systems in Europe and solar power in the US.

Geoff Bertram, a former economics lecturer at Victoria University said SOEs had been using the assets they inherited from previous government agencies as "cash cows" to fund higher risk speculative ventures.